Editing Trill (section)

==Joining==

On average, only 300 symbionts are available for hosting each year. Because there are many more humanoid Trill than symbionts, prospective hosts are weeded out by a demanding selection procedure, overseen by the Symbiosis Commission.  The competition for the few symbionts is fierce and attracts the brightest and most highly motivated of Trill society. Often the would-be hosts excel in their chosen fields and it is not uncommon for them to hold several degrees or distinctions prior to their joining. Prospective hosts may eventually become initiates under the supervision of a field docent, a joined Trill who evaluates the prospective host's suitability for joining and makes a recommendation to the Commission. A negative recommendation usually means the initiate is cut from the joining program. 

Common knowledge in Trill society dictates that only 1 in 1000 Trill make acceptable hosts; in fact, this figure is vastly inflated, and is closer to 1 in 2, but the myth is perpetuated very carefully in order to avoid the widespread chaos which would arise if the information were made public. 

Unless the joined Trill objects, a prospective host may request a specific symbiont. If a host is weak, the personality of the symbiont will overwhelm it. The joined Trill has several tools at their disposal for dealing with various aspects of their previous hosts. The telepathic ceremony of Zhian'tara allows a current host to divest the symbiont of the personality and all the memories of a previous host, which are temporarily hosted in volunteers. The transferring process is performed and supervised by a symbiont guardian, an unjoined Trill telepath. The ceremony creates a chance for closure by having the new host address the previous hosts directly as a means of distinguishing their voices and cementing the sense of finality of its latest transition. Similary, the Rite of Emergence can focus the voice of a single previous host among the memories of the other, allowing for a more direct converse in times of need for the current host.

The Zhian'tara ritual is roughly similar to the Vulcan fal-tor-pan ritual, since both enable the respective species to perform a synaptic pattern displacement, the transfer of what could be considered as a soul (katra, pagh etc.).